Spark plug recomendations

[Furyos George]

Hi all,
just wanting to know what plugs people are using, time for a new set with my new heads and may try a new type. Have been using ngk bp5s. Havnt been bad plugs, but my engine builder says they look stressed and I was running way too much gap (.060) and have been getting bad combustion.
Engine is a 400 stroker (470)
forged pistons, crank, rods. 9.6 compression. has a heavily ported set of 452 heads, edelbrock performer rpm and thunder 800 carb. Ignition is msd 6al, msd billet distributer, msd 9mm leads and blaster 2 coil.
My engine builder is suggesting trying multi electrode plugs like a split fire or e3, but ive heard they are a load of rubbish?
another option is ngk r 5670-6, or should I just go back to the tried and true champion j12y?

thanks

 

[commando1]

The lowest priced ones I can find which are usually Champion. J12Y.
After making the same damn plug a trillion gazillion times over and over forever, I think they got it right.

Posted via Topify on Android

 

[1966newport]

ngk ..

 

[440Sled]

Champion @ .040

 

[saylor]

+1. get the cheapest plug you can find.
throw away the dual-point platinum tip plugs they suck.

whatever plugs you had that worked @ .60 , ,use those same plugs, but @ .35 - .40 gap.

if they were sparking @ .60 gap, they will work fantastically at the correct gap.

 

[Furyos George]

Thanks for the input everyone, I am gonna stick with the plain NGK plugs because they are available at any auto store near me, but gonna try one step cooler , a bp6s., gapped to .40

 

[commando1]

WHOA!!!!!!!!!
I just reread your specs and saw that you're using 452 heads.
THEY DON'T TAKE THE NORMAL 440 PLUG.
You have to use a GM "peanut plug"!!

That's why they were stressed!

http://board.moparts.org/ubbthreads...=7053600&Words=+392charger&topic=&Search=true

http://speedtalk.com/forum/viewtopic.php?f=1&t=32773&start=15

http://ramchargercentral.com/vehicle-help/440-spark-plugs/25/

https://www.google.com/search?q=452...4&sourceid=chrome&espv=210&es_sm=122&ie=UTF-8

They were stressed because you were using the wrong design plug.
Here:

Wish I had caught that earlier.

 

[commando1]

J12Y

RJ12Y

 

[commando1]

You plug never seated correctly because that nub was cast in there to prevent installing the incorrect plug.

 

[70bigblockdodge]

Was it missing or breaking up if not you have no problem.

 

[commando1]

Someone's not hearing me...

 

[70bigblockdodge]

I mean if they don't fit that's one, thing but as long as they are lighting the fire there is not much to gain.

 

[commando1]

I'm saying they didn't fit.
You can JAM J12Y's into there but they won't seat correctly. Crushed washer vs. tapered seat.
I've seen 452's with the nub ground off because they didn't know better.

 

[70bigblockdodge]

Learn something everyday.

 

[Furyos George]

Thanks commando1, you just saved me buying a set of wrong plugs. The motor has had mild 906 heads for the last year, and the heavily ported 452 heads are being installed at the moment. Im due to pick it up next weekend. so will have a look at these peanut plugs, they should be avalible locally if the go in chevs as well

 

[Furyos George]

70bigblock dodge, no it didn't really have a miss or stall or anything, it is a real beast at 3000rpm, but was going flat at 5000rpm. engine builder says ive been running it a bit lean, so will change out the jets up a step or two rich

 

[commando1]

but was going flat at 5000rpm

Unless you're going with a new crank, H-beam rods, 100% ARP bolts, etc, etc, etc,
I'd stop right there on a BB

 

[70bigblockdodge]

70bigblock dodge, no it didn't really have a miss or stall or anything, it is a real beast at 3000rpm, but was going flat at 5000rpm. engine builder says ive been running it a bit lean, so will change out the jets up a step or two rich

I had same problem with a 440 in bro in law challenger turns out throttle wasn't opening all the way that's what I get not double checking when I installed.

 

[Furyos George]

Just as a follow up to this, I got my motor back last night with the 452 heads on it, and they have a flat seat, not a tapered seat. They definitely take the same plugs as my last heads, so I guess these 452's came off a passenger car, not a motor home??
Anyway, I am getting a set of NGK bp6s plugs, gap them to .040 and see how we go.

Thanks all

 

[commando1]

OK. You're good.
452:..................................................................................452MH